Re: PATCH: domtree_build() creates extraneous bb->doms entries

[Luc Van Oostenryck <luc.vanoostenryck@gmail.com>]

On Thu, Jan 23, 2020 at 04:27:41PM +0800, Xan Phung wrote:
> Hi, I use Sparse's domtree_build() as the basis of my C implementation of
> the "Relooper" algorithm. I notice domtree_build appears to have a "memory
> leak" (this is an oversimplification of the problem, but not far off the
> truth).
> 
> Specifically, each time domtree_build gets called, extraneous/duplicated
> child nodes get left in the bb->doms ptrlist.  This is because the existing
> children are not cleared from bb->doms ptr list before rebuilding it.  (If
> you want to reproduce this problem, I can supply a demo of it comprising a
> test input source file and a modified test-linearized.c, which calls
> domtree_build repeatedly and reports the memory allocation stats).
> 
> In addition to consuming memory, the extraneous child nodes cause problems
> with my Relooper algorithm (as it results in a malformed dominance tree
> when walking down bb->doms).

Yes, indeed. The leak is one thing but the correctness is another one.

> The following 3 line patch fixes this problem:

Yes, that should do it. Thank you.

For me to take your patch would you mind to add your Signed-off-by,
certifying that you wrote the patch? Details can be found, for example,
at https://www.kernel.org/doc/html/latest/process/submitting-patches.html#sign-your-work-the-developer-s-certificate-of-origin

-- Luc